Gillard ‘smear’ has no credibility: Swan

Treasurer Wayne Swan says the ongoing union funds saga is the result of an opposition smear campaign fuelled by the stories of a "crook".

Media outlets and the opposition say Prime Minister Julia Gillard has "questions to answer" over her connections to a Australian Workers Union (AWU) fund when she was a lawyer with Slater & Gordon in the 1990s.

But Mr Swan says the story has little credibility because it emanates from former AWU official Ralph Blewitt, who has admitted to engaging in fraud.

"This is a smear campaign which is not based on any facts and comes from someone who has admitted being involved in fraudulent activity," Mr Swan told reporters in Brisbane on Saturday.

"I don't think anyone takes those statements with a grain of credibility.

"What we're seeing here is effectively a crook who has been joined by elements of the Liberal Party in a smear campaign against the prime minister."

Nick Styant-Browne, a former Slater & Gordon partner, this week raised questions about Ms Gillard's connection to a mortgage on a property bought by her former boyfriend and AWU official Bruce Wilson.